FR3023703A1 - DEVICE FOR TREATING A BLOOD CIRCULATION CONDUIT - Google Patents

Abstract

The device comprises: - a tubular stent (16) of central axis (A-A '), and a delivery system (14) comprising a capsule (32) defining an interior volume (72) receiving the tubular stent (16). ) in its contracted state. The capsule (32) is movable relative to the tubular stent (16) along the central axis (A-A ') between a stent position of the tubular stent (16) and a release position of the tubular endoprosthesis (16). tubular stent (16). The device includes an opening mechanism (38) for the capsule (32) adapted to be operated in the overlap position to pass the capsule (32) from a closed configuration of the tubular stent (16) to a radially expanded open configuration of release of the tubular stent (16). The tubular stent (16) is adapted to be kept at least partially retracted into the interior (72) as the cap (32) passes from its closed configuration to its open configuration.

Description

The present invention relates to a device for treating a blood circulation conduit, comprising: a central axis tubular stent, deployable between a contracted state and an expanded state; a tubular endoprosthesis delivery system having a capsule defining an interior volume receiving the tubular stent in its contracted state, the capsule being movable relative to the tubular stent along the central axis between a recovery position of the tubular stent and a release position of the tubular stent. This device is particularly applicable to the treatment of heart valves. The heart has valves that are present at the outlet of the right ventricle (pulmonary valve and tricuspid) and the left ventricle (aortic and mitral valve). These valves provide unambiguous flow of blood, avoiding blood reflux after ventricular contraction. However, diseases or malformations affect the proper functioning of the valves. In particular, these may suffer from calcification thus allowing reflux or regurgitation to the ventricle or atrium that has expelled blood flow. The problem of regurgitation leads to an abnormal dilation of the ventricle which eventually produces heart failure. In some cases, the valve includes a number of sheets lower than that generally observed for this type of valve, which can affect its operation in the long term. To treat this type of disease surgically, it is known to implant an endovalve between the leaflets of the sick native valve. This endovalve comprises a tubular stent formed by an autoextensible lattice and a flexible closure or valve made most often in a tissue of animal origin. The flexible obturator is fixed permanently in the stent. Such endovalves are implantable endoluminally, which considerably limits the risks associated with the implantation of the valve, especially in terms of mortality. To promote endoluminal implantation, it is necessary to reduce as much as possible the size of the endoprosthesis carrying the valve during its path through the blood circulation ducts to the valve to be treated. For this purpose, the stent in its contracted configuration is housed in a capsule located in the vicinity of the nose of the delivery system. US 2005/090834 discloses a stent delivery system of the aforementioned type. To deploy the stent, the capsule is moved axially relative to the stent. When the latter is self-expanding, it deploys radially to make contact with the walls of the duct in which it is implanted. Such a delivery system is not entirely satisfactory. Indeed, the axial withdrawal of the capsule relative to the stent is sometimes difficult to achieve, especially when the capsule firmly encloses the stent. In this case, the radial forces applied by the capsule to the stent increase the axial friction between the capsule and the stent. To limit this friction, it is possible to slightly increase the radial extent of the capsule. However, this increases the bulk of the delivery system, and complicates its introduction into the bloodstream of the patient.

An object of the invention is to obtain a particularly compact treatment device, but which nevertheless remains very simple to set up in a blood circulation conduit. To this end, the subject of the invention is a device of the aforementioned type, characterized in that the device comprises a mechanism for opening the capsule adapted to be operated in the covering position to pass the capsule of a closed configuration of retaining the tubular stent in a radially expanded open release configuration of the tubular stent, the tubular stent being adapted to be retained at least partially retracted into the interior volume as the capsule is passed from its closed configuration to its configuration opened.

The device according to the invention may comprise one or more of the following characteristics, taken separately or in any technically possible combination: the opening mechanism is capable of releasing at least one lateral passage through the capsule during the passage of the capsule from its closed configuration to its open configuration. - The edges of the lateral passage in the open configuration are located in contact with each other in the closed configuration. - The opening mechanism comprises at least one cutting member of the capsule, the lateral passage being created by cutting the capsule during the operation of the opening mechanism. - The capsule defines the lateral passage, the opening mechanism comprising at least one closure member of the lateral passage releasable during the operation of the opening mechanism. - The tubular stent is able to remain confined in the interior volume out of the side passage during the operation of the opening mechanism. the tubular stent is deployable spontaneously from its contracted state to its expanded state, the delivery system comprising a retaining assembly of the tubular stent, the retaining assembly being adapted to maintain at least a portion of the tubular stent in its contracted state, during the passage of the capsule from its closed configuration to its open configuration. the retaining assembly comprises at least one releasable filiform link defining a retaining loop encircling the tubular stent. - The retaining assembly comprises a hollow stent delimiting a retaining aperture through which the filiform link is engaged, the filiform link having a control portion operable by a user from a proximal end of the guardian. - The tubular stent is maintained spontaneously in its contracted configuration, the delivery system comprising a radial deployment balloon of the tubular stent to its deployed configuration. the capsule in the closed configuration encloses the tubular stent in the contracted state, the axial retention force of the tubular stent in the capsule in the closed configuration being greater than the axial retention force of the tubular stent in the capsule in open configuration. The invention also relates to a stent release method comprising the following steps: - providing a device as described above; opening the capsule with the opening mechanism to move the caspule from a closed endoprosthesis holding configuration to a radially expanded open stent release configuration, the stent being retained in the stent; internal volume by the restraint assembly during the passage of the capsule from its closed configuration to its open configuration. The invention will be better understood on reading the description which will follow, given solely by way of example, and with reference to the appended drawings, in which: FIG. 1 is a side view of a first device; process according to the invention, the capsule occupying a closed configuration receiving the stent; - Figure 2 is a view taken in partial section along a median axial plane of the first processing device; FIG. 3 is a view, taken end-to-end from the distal end of the first device of FIG. 1, the nose having been removed; - Figure 4 is a view similar to Figure 1, after opening of the capsule, and before its axial displacement relative to the stent; FIG. 5 is an end view of FIG. 4; - Figure 6 is a view similar to Figure 4, after the axial displacement of the capsule relative to the stent; - Figure 7 is a view similar to Figure 6, after removal of the retaining assembly of the stent and the capsule; - Figure 8 is a view similar to Figure 1 of a second processing device according to the invention; - Figure 9 is a view similar to Figure 2 of a third processing device according to the invention. A first treatment device 10 according to the invention is illustrated in FIGS. 1 to 7. This device 10 is intended to be introduced into a blood circulation conduit of a patient. The device 10 comprises a prosthetic implant 12, intended to be placed in the blood circulation duct, and a delivery system 14 of the prosthetic implant 12. In this example, the prosthetic implant 12 is an endovalve. The implant 12 comprises a tubular stent 16, and a prosthetic valve 18 mounted in the tubular stent 16. As shown in Figure 7, the tubular stent 16 is formed by a perforated tubular armature 20 of central axis AA 'comprising a wire mesh which has spring properties. The armature 20 is for example obtained by braiding at least one stainless steel wire, a shape memory alloy, or a polymer.

Alternatively, the armature 20 is obtained by laser cutting a tube or other technique. The armature 20 defines an inner peripheral surface and an outer peripheral surface about the axis A-A '. The inner peripheral surface defines a central passage 22 for blood circulation. The outer peripheral surface is intended to be applied at least partially against a wall of the blood circulation duct and / or against the native leaflets. The armature 20 of the stent 12 is deployable between a contracted state, in which it has a small diameter, for introduction into the conduit, and an expanded state, constituting its state of rest, in which it has a large diameter. In the example shown in Figures 1 to 4, the armature 20 is deployable spontaneously between its contracted state and its expanded state. The valve 18 is for example made based on a native valve of an animal such as a pig or others. Alternatively, it is made from natural tissues such as bovine or ovine pericardium, or based on synthetic fabrics. In a conventional manner, the valve 18 comprises a tubular base fixed on the inner surface of the frame 20, and flexible sheets for closing the central passage 22, for example three in number. The sheets are movable radially towards the axis of the passage 22 between a closed position, in which they substantially completely prevent the passage of blood through the passage 22, and a release position of the passage 22 in which they are substantially pressed against the inner surface of the stent 16 and in which they let the blood pass through the passage 22. With reference to Figure 1, the delivery system 14 comprises an outer sheath 30 of central axis B-B ', a capsule 32 receiving the implant 12, disposed at the distal end of the outer sheath 30, and a nose 34 distally sealing the capsule 32. Referring to Figure 2, the release system 14 further comprises a releasable assembly 36 retaining the implant 12 in the delivery system 14, and, according to the invention, a mechanism 38 of longitudinal opening of the capsule 32 to pass from a closed configuration to an open configuration. As can be seen in FIG. 1, the outer sheath 30 comprises a proximal section 50 intended to be kept out of the patient, an intermediate section 52 and a head 54, the section 52 and the head 54 being intended to be introduced into the blood network. of the patient. The sheath 30 defines a central passage 56 for circulation of the releasable retaining assembly 36 and a peripheral passage 57 for the circulation of the opening mechanism 38 which is distinct or coincident with the central passage 56. The proximal section 50 delimits in this example a proximal axial opening 58 through which the central passage 56 opens. It comprises a member 60 for actuating the releasable retaining assembly 36 and a branch 62 for actuating the opening mechanism 38.

The intermediate section 52 is elastically deformable by flexion to circulate in the bloodstream of the patient. It has for example a maximum diameter of between 3 mm and 7 mm. The head 54 is disposed at the distal end of the outer sheath 30. The central passage 56 opens axially through the head 54. In this example, the head 54 has a radial extent greater than that of the intermediate section 52 and defines a shoulder 64 with the intermediate portion 52. The capsule 32 is attached to the outer sheath 30 at its distal end. In a variant, the capsule 32 is integral with the outer sheath 30.

The capsule 32 comprises a tubular sleeve 70 of central axis B-B 'defining an internal volume 72 for receiving the implant 12. In this example, the tubular sleeve 70 is made of plastic, for example polytetrafluoroethylene. It has a wall thickness less than the wall thickness of the outer sheath 30. This wall thickness is for example less than 0.15 mm, and especially between 0.5 mm and 0.1 mm, or between 0 , 1 mm and 0.05 mm. The outer peripheral surface of the capsule 32 is flush with the outer peripheral surface of the outer sheath 30 at the head 54. The length of the capsule 32 taken along the axis BB 'is greater than that of the implant 12 Thus, the implant 12 is able to be totally contained in the capsule 32. In this example, the wall of the capsule 32 is solid, with the exception of through openings 74 through which the opening mechanism 38 passes, which open into the interior volume 72. The capsule 32 is able to pass from a closed implant retainer configuration 12, visible in FIGS. 2 to 3, to a radially expanded open configuration of the release of the implant 12, visible Figures 4 and 5. In the closed configuration, the capsule 32 has a minimum transverse extent. Its maximum outside diameter is for example less than 9 mm and is in particular between 9 mm and 3 mm.

The stent 16 is maintained in its contracted state, with its outer surface in contact with the inner surface of the capsule 32. The capsule 32 encloses the stent 16. In the open configuration, side passages 78 have been opened in the capsule 32 by the opening mechanism 38. The lateral passages 78 extend along the capsule 32, advantageously parallel to the axis A-A '.

The transverse extent of the capsule 32 is then increased. Its maximum outside diameter is, for example, greater than more than 150% of the outside diameter in the closed configuration. According to the invention, the stent 16 is maintained at least partially in its contracted state through the releasable retaining assembly 36. The inner surface of the capsule 32 has moved at least partially away from the outer surface of the the tubular stent 16. The outer sheath 30 and the outer sheath 32 are movable jointly along the axis AA 'relative to the implant 12, between a distal overlap position of the implant 12, visible in FIG. 2, in which the implant 12 is received in the internal volume 72 and a proximal position of release of the implant 12, visible in FIG. 6, in which the capsule 32 is offset axially with respect to the implant 12. releasable retaining assembly 36 is for example of the type described in the French application FR2863160. It comprises in this example a hollow stent 80 disposed through the inner volume 72, a filamentary retaining link 82, partially surrounding the stent 16, and a rod 84 retaining the filiform link. Guardian 80 comprises a hollow flexible metal tube. The internal diameter of the tube is adapted to thread it onto a filamentary surgical guide (not shown) installed on the patient, prior to the introduction of the stent 16 in a blood vessel of this patient. The stent 80 extends longitudinally between a distal end intended to be implanted in the blood vessel and a proximal end intended to be accessible to a surgeon. A distal retaining aperture 86 associated with the filiform link 82 is formed laterally in the guardian 80. The retaining rod 84 is disposed in the guardian 80. The rod 84 is movable in translation in the guardian 80, between a retaining position, in which it is placed facing the retaining aperture 86, and a release position, in which it is placed away from the retaining apertures 86.

In the example shown in FIG. 3, the assembly 36 comprises a single filiform link 82. In a variant, the assembly 36 comprises several filiform links 82. As can be seen in FIGS. 5 and 6, the filiform link 82 here comprises a single strand, which has an end runner 87, a clamping loop 88, and a control section 89.

End pass 87 is disposed at a distal end of the strand. It is formed of a closed loop. The rod 84 is engaged in the loop 87, when the rod 84 is in its retaining position. The loop 87 is also deformable so that its width, when deformed is substantially equal to twice the width of the strand. The loop 87 is connected to the clamping loop 88 by a section engaged in the distal retaining aperture 86. The clamping loop 88 is formed by a section of the strand engaged around the stent 16.

The clamping loop 88 extends between a retaining end connected to the loop 87 and a clamping end connected to the control section 89 and engaged in the retaining opening 86. This clamping loop 88 fixes the stent 16 to the guardian 80 in the vicinity of the distal end of this guardian 80. The active length of the clamping loop 88 is variable, so that it controls the deployment of the stent 16 relative to the stent 80, as will be described more low. The control section 89 extends in the stanchion 80 between the distal retaining aperture 86 and the actuating member 60 on which it is engaged. The length of the control section 89 engaged on the operating member 60 is variable and controls the length of the clamping loop 88. Thus, an increase in the length of the control section engaged on the operating member 60 causes a decrease corresponding to the active length of the clamping loop 88, and consequently the clamping of the stent 16 against the stent 80, at the level of the clamping loop 88.

When the stent 16 is in its contracted state against the stent 80, the control section 89 is in a tensioned position. Conversely, a decrease in the length of the control section engaged on the operating member 60 causes an increase in the active length of the clamping loop 88 and consequently, the deployment of the stent 16 away from the stent 80 at the clamping loop 88. When the stent 16 is in its expanded state, the control section 89 is in a relaxed position. In this example, with reference to FIGS. 1 and 2, the opening mechanism 38 of the capsule 32 comprises at least one longitudinal cutting member 100 for the capsule, which can be controlled from the proximal end of the delivery system 14 to open a lateral passage 78 through the capsule 32 (visible in Figure 4).

The opening mechanism 38 here comprises several parallel cutting members 100, each adapted to open a longitudinal passage 74 through the wall of the capsule 32. The longitudinal cutting member 100 is for example formed by a cutting wire folded into loop around the wall of the capsule. The cutting wire comprises an inner strand 102 and an outer strand 104 interconnected at their distal end 106. The inner strand 102 comprises a distal section, substantially parallel to the axis A-A ', disposed in the interior volume 72, between the stent 16 and the capsule 32, and a proximal section engaged in the sheath 30 to the branch 62.

The outer strand 104 has a distal section disposed outside the capsule 32 substantially parallel to the axis B-B ', along its outer peripheral surface between the distal edge of the capsule 32 is a through opening 74. It comprises a section intermediate engaged in the interior volume 72 through the opening 74, and a proximal section engaged in the sheath 30 to the branch 62.

The longitudinal cutting member 100 is adapted to be pulled proximally from the branch 62 to the outside of the patient's body between a distal position, visible in FIG. 1, in which the distal end 106 is disposed initially. around the distal edge of the capsule 32, and a proximal position, visible in Figure 4, in which the distal end 106 has moved to a proximal edge of the capsule 32 and cut longitudinally the capsule 32 to create a passage lateral 78 opening into the interior volume 72. The operation of the first processing device 10 will now be described. Initially, the delivery system 14 is provided, with its releasable retaining assembly 36. The stent 80 protrudes proximally beyond the proximal edge of the capsule 32. The clamping loop 88 projects out of the opening of the Retention 86. The capsule 32 is in its closed configuration. The operator selects an appropriate implant 12 to be implanted in the patient. He arranges the implant 12 in its dilated state around the stent by introducing the stent into the central passage 22. Then, it places the clamping loop 88 around the tubular stent 16, so that it surrounds the stent 16. It then actuates the operating member 60 to reduce the active length of the clamping loop 88 and pass the stent 16 at least partially in its contracted state. Then, he introduces the endoprosthesis 16 into the inner volume 72 of the capsule 32 by compressing its proximal edge and relatively moving the capsule 32 and the stent 80. The capsule 32 then occupies its distal stent recovery position. 16, visible in Figure 1. The stent 16 is then maintained very confined in the inner volume 72 of the capsule 32 occupying its closed configuration. The radial size of the processing device 10 is then minimal. Then, the operator inserts a surgical guide into the body of the patient endoluminally, to the implantation site of the implant 12. He engages the treatment device 10 around the surgical guide to introduce it into the body of the patient. patient and bring the capsule 32 to the site of implantation by maintaining the operating member 60, the branch 62 and the proximal end of the outer sheath 30 outside the patient. This being done, the operator actuates the opening mechanism 38 to pass the capsule 32 in its open configuration. In the configuration illustrated in FIGS. 1 to 7, the operator pulls on the cutting member 100 through the branch 62. He moves the cutting member 100 from its distal position to its proximal position to bring the end closer together. distal 106 of the proximal edge of the capsule 32. This displacement longitudinally cuts the capsule 32 and creates at least one lateral passage 78. The capsule 32 expands, so that the inner volume 72 increases radially.

According to the invention, the retaining assembly 36 maintains the stent 16 at least partially in its contracted state. The stent 16 therefore remains contained in the inner volume 72, without protruding from the lateral passages 78 open in the capsule 32. The operator can then move the capsule 32 relative to the stent 16 to discover the stent 16. At least one passage 78 having been opened laterally, the capsule 32 in the open configuration no longer surrounds the stent 16 as in the closed configuration. The axial displacement of the capsule 32 relative to the stent 16 is easy to achieve and does not require overcoming a significant frictional force.

However, thanks to the presence of the releasable retaining assembly 36 active during the opening of the capsule 32, the stent 16 remains at least partially in its contracted state. It can therefore be positioned precisely and reversibly at its location. Then, the operator actuates the operating member 60 to release the filiform links and increase the active length of the clamping loop 88. The stent 16 extends radially and comes into contact with the wall defining the blood circulation conduit and / or with the leaflets of the native valve. If the operator is not satisfied by the positioning of the stent 16, he actuates again the operating member 60 to reduce the active length of the clamping loop 88 and retract at least partially the stent 16. When the operator estimates that the stent 16 is positioned correctly, it releases the end loop 87 of the clamping loop 88 by removing the retaining pin 84, as shown in FIG. 7. Then, it extracts the retaining rod 84, the filiform link 82 and the guardian 80 out of the patient.

The device 10 according to the invention is therefore particularly compact, while allowing a simple release of the implant 12 by the opening of the capsule 32, the deployment of the implant 12 remaining controlled by the releasable retaining assembly 36. In a variant shown in Figure 8, the capsule 32 is formed with an existing lateral passage 78. The edges of the side passage 78 are assembled one on the other by the opening mechanism 38. For this purpose, a filiform member 140 is for example sewn between the edges of the side passage 78. The filiform member 140 is removed to pass the capsule 32 of the closed configuration to the open configuration by opening the lateral passage 78. In another variant, shown in Figure 9, the stent 16 is kept at rest in its contracted state. A balloon 150 is inserted between the stent 80 and the inner surface of the stent 16. As previously, the operator opens the capsule 32 longitudinally using the opening mechanism 38, then discovers the stent 16 by moving the stent. outer sheath 30 with respect to the stent 16.

The endoprosthesis 16 is not deployable spontaneously, it remains in its contracted state. The operator then inflates the balloon 150 at the selected location of implantation to pass the stent 16 in its expanded state. The stent 16 is held extremely compactly in the capsule 32 during its transport to the implantation site in the delivery system 14, while being easily removable from the capsule 32 once it is open. Since the stent 16 is not deployable spontaneously, its deployment at the implantation site is controlled and is posterior to the opening of the capsule 32.

Claims (11)

CLAIMS1.- A device (10) for treating a blood circulation conduit comprising: a tubular stent (16) of central axis (A-A '), deployable between a contracted state and an expanded state, - a system delivery device (14) of the tubular stent (16) having a capsule (32) defining an interior volume (72) receiving the tubular stent (16) in its contracted state, the capsule (32) being movable relative to the tubular stent (16) along the central axis (A-A ') between a stent position of the tubular stent (16) and a release position of the tubular stent (16); characterized in that the device (10) comprises an opening mechanism (38) of the capsule (32) adapted to be operated in the overlapping position to pass the capsule (32) of a closed configuration of retaining the tubular stent (16) having a radially expanded open release configuration of the tubular stent (16), the tubular stent (16) being adapted to be retained at least partially retracted into the inner volume (72) as it passes through the tubular endoprosthesis (16). capsule (32) from its closed configuration to its open configuration. 2.- Device (10) according to claim 1, wherein the opening mechanism (38) is adapted to release at least one lateral passage (78) through the capsule (32) during the passage of the capsule (32). from its closed configuration to its open configuration. The apparatus (10) of claim 2, wherein, the edges of the lateral passage (78) in the open configuration are in contact with each other in the closed configuration. 4.- Device (10) according to one of claims 2 to 3, wherein the opening mechanism (38) comprises at least one cutting member (100) of the capsule (32), the lateral passage (78) being created by cutting the capsule (32) during the operation of the opening mechanism (38). 5.- Device (10) according to any one of claims 2 to 3, wherein the capsule (32) defines the lateral passage (78), the opening mechanism (38) having at least one closing member (140). ) of the lateral passage (78) releasable during the operation of the opening mechanism (38). 6.- Device (10) according to any one of claims 2 to 5, wherein the tubular stent (16) remains confined in the inner volume (72) out of the side passage (78) during the operation of the mechanism d opening (38). 7. A device (10) according to any one of the preceding claims, wherein the tubular stent (16) is deployable spontaneously from its contracted state to its expanded state, the delivery system (14) comprising a restraint assembly ( 36) of the tubular stent (16), the retainer assembly (36) being adapted to maintain at least a portion of the tubular stent (16) in its contracted condition as the cap (32) passes through. its closed configuration to its open configuration. The device (10) of claim 7, wherein the retainer assembly (36) includes at least one releasable wire link (82) defining a retaining loop (88) surrounding the tubular stent (16). The apparatus (10) of claim 8, wherein the retainer assembly (36) includes a hollow stanchion (80) defining a retaining aperture (84) through which the filamentary link (82) is engaged, the filamentary link (82) having a control portion operable by a user from a proximal end of the guard (80). 10.- Device (10) according to any one of claims 1 to 6, wherein the tubular stent (16) is maintained spontaneously in its contracted configuration, the delivery system (14) comprising a balloon (150) deployment radial of the tubular stent (16) to its deployed configuration. 11.- Device (10) according to any one of the preceding claims, wherein the capsule (32) in the closed configuration encloses the tubular stent (16) in the contracted state, the axial retention force of the stent tubular (16) in the capsule (32) in the closed configuration being greater than the axial retention force of the tubular stent (16) in the capsule (32) in open configuration.